DOCSLIB.ORG

Status of Native Fishes in the Western United States and Issues for Fire

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Status of Native Fishes in the Western United States and Issues for Fire Forest Ecology and Management 178 (2003) 197–211 Status of native fishes in the western United States and issues for fire and fuels management Bruce Riemana,*, Danny Leeb, Dave Burnsc, Robert Gresswelld, Michael Younge, Rick Stowellf, John Rinneg, Philip Howellh aUS Forest Service, Rocky Mountain Research Station, 316 East Myrtle Street, Boise, ID 83702, USA bUS Forest Service, Pacific Southwest Research Station, 1700 Bayview Drive, Arcata, CA 95521, USA cUS Forest Service, Payette National Forest, 800 West Lakeside Avenue, McCall, ID 83638, USA dUSGS Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331, USA eUS Forest Service, Rocky Mountain Research Station, P.O. Box 8089, Missoula, MT 59807, USA fUS Forest Service, Region 1, P.O. Box 7669, Missoula, MT 59807, USA gUS Forest Service, Rocky Mountain Research Station, 2500 South Pine Knoll, Flagstaff, AZ 86001, USA hUS Forest Service, Pacific Northwest Research Station, 1401 Gekeler Lane, La Grande, OR 97850, USA Abstract Conservation of native fishes and changing patterns in wildfire and fuels are defining challenges for managers of forested landscapes in the western United States. Many species and populations of native fishes have declined in recorded history and some now occur as isolated remnants of what once were larger more complex systems. Land management activities have been viewed as one cause of this problem. Fires also can have substantial effects on streams and riparian systems and may threaten the persistence of some populations of fish, particularly those that are small and isolated. Despite that, major new efforts to actively manage fires and fuels in forests throughout the region may be perceived as a threat rather than a benefit to conservation of native fishes and their habitats. The management of terrestrial and aquatic resources has often been contentious, divided among a variety of agencies with different goals and mandates. Management of forests, for example, has generally been viewed as an impact on aquatic systems. Implementation of the management-regulatory process has reinforced a uniform approach to mitigate the threats to aquatic species and habitats that may be influenced by management activities. The problems and opportunities, however, are not the same across the landscapes of interest. Attempts to streamline the regulatory process often search for generalized solutions that may oversimplify the complexity of natural systems. Significant questions regarding the influence of fire on aquatic ecosystems, changing fire regimes, and the effects of fire-related management remain unresolved and contribute to the uncertainty. We argue that management of forests and fishes can be viewed as part of the same problem, that of conservation and restoration of the natural processes that create diverse and productive ecosystems. We suggest that progress toward more integrated management of forests and native fishes will require at least three steps: (1) better integration and development of a common conceptual foundation and ecological goals; (2) attention to landscape and ecological context; and (3) recognition of uncertainty. Published by Elsevier Science B.V. Keywords: Wildfire; Fire and fuels management; Native fish; Conservation; Restoration * Corresponding author. Tel.: þ1-208-373-4386; fax: þ1-208-373-4391. E-mail address: [email protected] (B. Rieman). 0378-1127/03/$ – see front matter. Published by Elsevier Science B.V. doi:10.1016/S0378-1127(03)00062-8 198 B. Rieman et al. / Forest Ecology and Management 178 (2003) 197–211 1. Introduction others (Hann et al., 1998; USDA, 2000) argue that the changes that have occurred may produce an unprece- Managers of public lands in the western United dented continuity of fuels and could lead to larger and States face a difficult challenge in restoration and more destructive fires than observed in the recent past. protection of native fishes and their habitats, while It also has been suggested that such fires are cat- simultaneously attempting to develop and implement astrophic from both socio-economic and ecological an effective landscape strategy for management of perspectives (see http://www.whitehouse.gov/infocus/ wildland fire. Native fishes now represent some of the healthyforests/sect5.html). Recent large fires in the most imperiled biological taxa in North America western US have seemingly underscored these pre- (Ricciardi and Rasmussen, 1999). In the western dictions and galvanized a political and agency will to US, a growing number of fishes are listed or petitioned respond. The National Fire Plan (NFP) (Laverty and for listing under the Endangered Species Act (ESA), Williams, 2000; USDA, 2000), other local or regional or are considered sensitive or of special concern by the initiatives, and funds allocated by Congress have agencies responsible for their management. Local and focused resources to reduce and manage fuels and regional extinctions of native fish have occurred over large fires, rehabilitate burned areas, and restore fire to the past century (Frissell, 1993; Lee et al., 1997), and a more natural role. One objective of the NFP is the many populations are restricted to small and often maintenance of clean water and biological diversity in isolated remnants of a much larger and more contin- fire-prone ecosystems. An important assumption is uous historical range (Moyle and Williams, 1990; that mitigation of changing fire patterns will directly Minckley and Deacon, 1991; Young, 1995; Lee benefit watersheds and habitats for sensitive species. et al., 1997). Remnant population networks and many As we discuss later this assumption may hold in some of the remaining strongholds for native species are contexts, but not others. Clearly, past management often found on public lands that now are key to the activities contributed to the disruption and degradation conservation of these species (Lee et al., 1997). In of watersheds and habitats for fishes (Lee et al., 1997). response, federal agencies have undertaken major Aggressive fuels treatments that mimic past land assessments of aquatic ecosystems, habitats, species, management activities (e.g. timber-harvest) could and the processes that influence them (e.g. FEMAT, simply exacerbate the problem. 1993; Quigley and Arbelbide, 1997), and proposed In this paper, we argue for finding common ground major initiatives to recognize, restore, and conserve in the management of native fishes and forests. sensitive populations and critical habitats (USDA, Ecosystem management concepts underscore inter- 1995; USDA/USDI, 1995, 2000; NMFS, 2000; connections among systems and reinforce the notion NWPPC, 2000). that maintenance of diverse and resilient ecosystems The rising concern for aquatic systems parallels an should be the primary constraint on management of all emerging dialogue on the management of forests. resources (Attiwill, 1994; ESA, 1995; Haynes et al., Decades of fire suppression, grazing, and selective 1996). Given that forest structure and composition, silvicultural and timber-harvest practices have led to and the natural processes that influence them, also changes in the structure and composition of some influence the creation and maintenance of productive forest types in the western US (Franklin, 1993; Veblen aquatic habitats and populations (Naiman et al., 1992; et al., 1994; Hessburg et al., 1999; Hessburg and Agee, Reeves et al., 1995; Franklin et al., 2001; Helfield and this issue). Change is most apparent in the drier mid- Naiman, 2001), management for wildland fire objec- and low-elevation forests where fires once burned tives cannot be isolated from the management of more frequently (e.g. 10–100 years), but generally native fishes, or vice versa. Broader recognition of were not stand replacing (Covington et al., 1997; the common issues and linkages between forests, fires, Everett et al., 2000; Hessburg and Agee, this issue). and the management of terrestrial and aquatic ecosys- Such change is not apparent in other forest types or in tems could provide a foundation for progress. all mid- and low-elevation forests (Romme and Other papers in this issue provide a context for the Knight, 1981; Veblen et al., 1994, 2000; Arno, changing patterns and management of fire and fuels 2000). Even so, Hessburg and Agee (this issue) and (Hessburg and Agee, this issue; Whitlock et al., this B. Rieman et al. / Forest Ecology and Management 178 (2003) 197–211 199 issue) and the role of fire-related disturbance in struc- 1986; Sheldon, 1988), but there are fewer than 70 turing stream channels and habitats (Benda et al., this native species found within the major western river issue; Meyer and Pierce, this issue; Miller et al., this basins such as the Columbia, Rio Grande, Colorado, issue). Dunham et al. (this issue) consider the biolo- and the Sacramento-San Joaquin (Sheldon, 1988; gical response of fish and fish populations to distur- Moyle and Williams, 1990; Lee et al., 1997). bance that may result from fire. In this paper, we Typical of systems elsewhere, much of the diversity outline the issues confronting managers of aquatic within these western river basins is found in the large, systems and fishes in particular as they begin to low-elevation rivers and estuaries. In contrast, much explore these ideas. We focus on fishes and aquatic simpler communities are found in the tributaries at ecosystems associated with the forested landscapes higher elevations. This has been attributed to more managed primarily by the US Forest Service and dynamic, extreme, and less productive
Load more

Recommended publications
  • Speleothem Paleoclimatology for the Caribbean, Central America, and North America
    quaternary Review Speleothem Paleoclimatology for the Caribbean, Central America, and North America Jessica L. Oster 1,* , Sophie F. Warken 2,3 , Natasha Sekhon 4, Monica M. Arienzo 5 and Matthew Lachniet 6 1 Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA 2 Department of Geosciences, University of Heidelberg, 69120 Heidelberg, Germany; [email protected] 3 Institute of Environmental Physics, University of Heidelberg, 69120 Heidelberg, Germany 4 Department of Geological Sciences, Jackson School of Geosciences, University of Texas, Austin, TX 78712, USA; [email protected] 5 Desert Research Institute, Reno, NV 89512, USA; [email protected] 6 Department of Geoscience, University of Nevada, Las Vegas, NV 89154, USA; [email protected] * Correspondence: [email protected] Received: 27 December 2018; Accepted: 21 January 2019; Published: 28 January 2019 Abstract: Speleothem oxygen isotope records from the Caribbean, Central, and North America reveal climatic controls that include orbital variation, deglacial forcing related to ocean circulation and ice sheet retreat, and the influence of local and remote sea surface temperature variations. Here, we review these records and the global climate teleconnections they suggest following the recent publication of the Speleothem Isotopes Synthesis and Analysis (SISAL) database. We find that low-latitude records generally reflect changes in precipitation, whereas higher latitude records are sensitive to temperature and moisture source variability. Tropical records suggest precipitation variability is forced by orbital precession and North Atlantic Ocean circulation driven changes in atmospheric convection on long timescales, and tropical sea surface temperature variations on short timescales. On millennial timescales, precipitation seasonality in southwestern North America is related to North Atlantic climate variability.
    [Show full text]
  • Threats to Western United States Riparian Ecosystems: a Bibliography
    Threats to Western United States Riparian Ecosystems: A Bibliography Boris Poff, Karen A. Koestner, Daniel G. Neary, and David Merritt United States Department of Agriculture / Forest Service Rocky Mountain Research Station General Technical Report RMRS-GTR-269 December 2012 Poff, Boris; Koestner, Karen A.; Neary, Daniel G.; Merritt, David. 2012. Threats to western United States riparian ecosystems: A bibliography. Gen. Tech. Rep. RMRS-GTR-269. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 78 p. Abstract __________________________________________________ This bibliography is a compendium of state-of-knowledge publications about the threats affecting western U.S. riparian ecosystems and is a companion to the website: http://www.rmrs.nau.edu/ awa/ripthreatbib/. The website contains abstracts and access to many of the publications via PDFs, or it directs the readers to websites where PDFs of the publication can be viewed or obtained. The bibliography is ordered alphabetically and the type of threats discussed in each publication is highlighted. These threats include agriculture, climate change, dam construction, disease, drought, invasive species, fire, floods, flow regulation, forest harvesting, grazing, groundwater depletion, insects, mining, recreation, roads, water diversions, urbanization, and water quality. Keywords: ecosystem, riparian, soil, water, watersheds, hydrology, threats, vegetation, wildlife, drought, floods, grazing, invasive plants Authors _____________________________ David Merritt, Riparian Ecologist, U.S. Department of Agri- culture, Rocky Mountain Research Station, Forest Service, Boris Poff, District Hydrologist, Bureau of Land Management, Stream Systems Technology Center, Fort Collins, Colorado. Las Vegas, Nevada. Karen A. Koestner, Hydrologic Research Technician, U.S. Acknowledgments ____________________ Department of Agriculture, Forest Service, Rocky Mountain Research Station, Forestry Sciences Laboratory, Flagstaff, This effort was funded by a grant from the U.S.
    [Show full text]
  • Contemporary Uplift of the Sierra Nevada, Western United States, from GPS and Insar Measurements
    Contemporary uplift of the Sierra Nevada, western United States, from GPS and InSAR measurements William C. Hammond1*, Geoffrey Blewitt1, Zhenhong Li2, Hans-Peter Plag1, and Corné Kreemer1 1Nevada Geodetic Laboratory, Nevada Bureau of Mines and Geology, and Nevada Seismological Laboratory, University of Nevada, Reno, Nevada 89557, USA 2Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET+), School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK ABSTRACT particular, the EarthScope Plate Boundary Observatory has provided hun- Modern space geodesy has recently enabled the direct observation dreds of new stations in California and Nevada, including about a dozen of slow geological processes that move and shape Earth’s surface, includ- on the west slope of the Sierra Nevada. We processed all available GPS ing plate tectonics and crustal strain accumulation that leads to earth- data to obtain station height time series, and fi t them with a six-parameter quakes. More elusive has been the direct observation of active moun- empirical model including an epoch position, a velocity, and an amplitude tain growth, because geodetic measurements have larger uncertainties and phase of annual and semiannual harmonic constituents (to model sea- in the vertical direction, while mountain growth is typically very slow. sonal effects). To enhance the signal-to-noise ratio, we used GPS vertical For the Sierra Nevada of California and Nevada, western United States, velocities based on over 3 yr of data with 1σ rate uncertainties ≤1.0 mm/yr, the history of elevation is complex, exhibiting features of both ancient and required that the empirical model adequately fi t the data (Fig.
    [Show full text]
  • Why Is Snow Important in the Southwestern United States
    Module 1 Educator’s Guide Investigation 4 Why is snow Geography Standards important in the Standard 7: Physical Systems The physical processes that shape southwestern the patterns of Earth’s surface • Describe how physical processes affect different regions of the United United States? States and the world. Investigation Overview Standard 15: Environment In Investigation 4, students role-play U.S. senators from seven western and Society states seeking to find solutions to important water problems in the How physical systems affect Southwest: recurrent drought, which reduces vital snowpack resources, human systems in the face of rapid population growth and therefore increasing demand • Analyze examples of changes in the on those resources. Information from satellite images, in tandem with physical environment that have ground-based perspectives, assist students in playing their roles as reduced the capacity of the environ- senators. Because the investigation uses a case study in the United ment to support human activity. • Apply the concept of “limits to growth” States, all statistics will be in English units. This conscious exception to to suggest ways to adapt to or the standard use of metric units reflects the real-world practice of Ameri- overcome the limits imposed on can water resource managers. human systems by physical systems. Time required: Five to nine 45-minute sessions (as follows): Standard 18: The Uses of Introduction and Parts 1 and 2: One or two 45-minute sessions Part 3: One 45-minute session Geography Parts 4 and 5: One or two 45-minute sessions How to apply geography to inter- Parts 6 and 7: One or two 45-minute sessions pret the present and plan for the Part 8 and Debriefing: One or two 45-minute sessions future • Develop policies that are designed to guide the use and management of Materials/Resources Earth’s resources and that reflect Briefing (one per student) multiple points of view.
    [Show full text]
  • Autumn Precipitation Trends in the Northeast United States
    Middle States Geographer, 2000, 33:74-81 AUTUMN PRECIPITATION TRENDS IN THE NORTHEAST UNITED STATES Keith G. Henderson Department of Geography Villanova University Villanova, PA 19085 ABSTRA CT: The northeastern United States experienced significant increases in precipitation from /900- / 999 Precipitation changes have been most prominent in the autumn. In western New York and Pennsylvania. and in coastal New England, seasonal precipitation totals have risen 25-45% over the IOO-year period. Concurrent decreases in temperature indicate that early season precipitation increases may be associated with earlier upper­ level troughing, while large-scale November changes may be linked to an enhanced subtropical high pressure system. Autumn precipitation steadily increased over the century and has impacted regional hydrology. At least three major rivers have shown increased autumn flow. This impact is potentially important given that autumn is usually a time ofrising river levels before high winter and spring runoffperiods. INTRODUCTION aI., 1996). Karl and Knight (1998) suggest that over half of the measured precipitation increase across the country has been caused by increases in the largest Recent research on global climate change 10% of storms. While precipitation events of all has highlighted precipitation trends as a leading levels have become more frequent, only the signal in change detection. In North America intensities of the largest events have increased (Karl precipitation has increased significantly in many and Knight, 1998). Kunkel et al. (1999) also found regions over the past century. Groisman and significant increases in extreme precipitation events Easterling (1994) found that total precipitation rose over many portions of the United States.
    [Show full text]
  • A Record-Breaking Trans-Atlantic African Dust Plume Associated with Atmospheric Circulation Extremes in June 2020 Bing Pu and Qinjian Jin
    Article A Record-Breaking Trans-Atlantic African Dust Plume Associated with Atmospheric Circulation Extremes in June 2020 Bing Pu and Qinjian Jin ABSTRACT: High concentrations of dust can affect climate and human health, yet our understanding of extreme dust events is still limited. A record-breaking trans-Atlantic African dust plume occurred during 14–28 June 2020, greatly degrading air quality over large areas of −3 the Caribbean Basin and the United States. Daily PM2.5 concentrations exceeded 50 µg m in several Gulf States, while the air quality index reached unhealthy levels for sensitive groups in more than 11 states. The magnitude and duration of aerosol optical depth over the tropical North Atlantic Ocean were the greatest ever observed during summer over the past 18 years based on satellite retrievals. This extreme trans-Atlantic dust event is associated with both enhanced dust emissions over western North Africa and atmospheric circulation extremes that favor long-range dust transport. An exceptionally strong African easterly jet and associated wave activities export African dust across the Atlantic toward the Caribbean in the middle to lower troposphere, while a westward extension of the North Atlantic subtropical high and a greatly intensified Caribbean low-level jet further transport the descended, shallower dust plume from the Caribbean Basin into the United States. Over western North Africa, increased dust emissions are associated with strongly enhanced surface winds over dust source regions and reduced vegetation coverage in the western Sahel. While there are large uncertainties associated with assessing future trends in African dust emissions, model-projected atmospheric circulation changes in a warmer future generally favor increased long-range transport of African dust to the Caribbean Basin and the United States.
    [Show full text]
  • Desertification of the American Southwest: an Analysis of Population, Climate, and Water Management
    IQP 2007-2008 Desertification of the American Southwest Desertification of the American Southwest: An analysis of Population, Climate, and Water Management. The Interactive Qualifying Project Report Submitted to the faculty Of the Worcester Polytechnic Institute In partial fulfillment of the requirement for the Interactive Qualifying Project By Kyle Forward, Ryan Blair and Nick Souviney Date: April 3, 2008 Advised by Professor Theodore C. Crusberg Worcester Polytechnic Institute 1 IQP 2007-2008 Desertification of the American Southwest Acknowledgements We would like to thank Professor T.C. Crusberg for his helpful guidance and support in writing this report. His knowledge of the area and first hand experience provided great insight into the region’s current problematic conditions. Worcester Polytechnic Institute 2 IQP 2007-2008 Desertification of the American Southwest Table of Contents ACKNOWLEDGEMENTS ......................................................................................................................... 2 TABLE OF FIGURES .................................................................................................................................. 4 TABLE OF TABLES .................................................................................................................................... 5 ABSTRACT ................................................................................................................................................... 6 POPULATION ...........................................................................................................................................
    [Show full text]
  • Climate Projections for the Midwest: Availability, Interpretation and Synthesis
    Climate Projections for the Midwest: Availability, Interpretation and Synthesis WHITE PAPER PREPARED FOR THE U.S. GLOBAL CHANGE RESEARCH PROGRAM NATIONAL CLIMATE ASSESSMENT MIDWEST TECHNICAL INPUT REPORT Julie A. Winkler1, Raymond W. Arritt2, Sara C. Pryor3 1 Department of Geography, Michigan State University 2 Department of Agronomy, Iowa State University 3 Department of Geological Sciences, Indiana University Recommended Citation: Winkler, J.A., R.W. Arritt, S.C. Pryor. 2012: Climate Projections for the Midwest: Availability, Interpretation and Synthesis. In: U.S. National Climate Assessment Midwest Technical Input Report. J. Winkler, J. Andresen, J. Hatfield, D. Bidwell, and D. Brown, coordinators. Available from the Great Lakes Integrated Sciences and Assessment (GLISA) Center, http://glisa.msu.edu/docs/NCA/MTIT_Future.pdf. At the request of the U.S. Global Change Research Program, the Great Lakes Integrated Sciences and Assessments Center (GLISA) and the National Laboratory for Agriculture and the Environment formed a Midwest regional team to provide technical input to the National Climate Assessment (NCA). In March 2012, the team submitted their report to the NCA Development and Advisory Committee. This white paper is one chapter from the report, focusing on potential impacts, vulnerabilities, and adaptation options to climate variability and change for the future climate sector. U.S. National Climate Assessment: Midwest Technical Input Report: Future Climate Sector White Paper Contents Summary ....................................................................................................................................................................................................................
    [Show full text]
  • The Geology of Western North America (Abridged Version)
    THE GEOLOGY OF WESTERN NORTH AMERICA (ABRIDGED VERSION) By JoAnne Nelson, British Columbia Ministry of Energy and Mines, Victoria, BC, Canada [email protected] The geological history of western North America has siliciclastic strata that are now beautifully exposed in the been, and continues to be, shaped by its position on the Canadian Rocky Mountains. The Mt. Brussilof magnesite eastern rim of the Pacific Ocean. The modern Pacific deposit is hosted by Middle Cambrian carbonate within Ocean’s basin is the successor of the original ocean which this continental shelf sequence. Equivalent platformal split Laurentia - our continent’s cratonic core - away from strata are best exposed in the southwestern United States, the rest of the Precambrian supercontinent Rodinia, an the Grand Canyon being a world-renowned example. The ocean that widened until in late Paleozoic time, it became opening of Panthalassa was not a single event in western Panthalassa, the World Ocean. Unlike the eastern side of North America: convincing Cambrian as well as late the continent, where continental collision was followed Proterozoic rift-related sequences occur, and alkalic to by re-opening of the Atlantic Ocean - the “Wilson cycle” ocean-floor basalts in the miogeocline range through - western North America has always faced the same Ordovician into Devonian age. The implied protracted active ocean basin. Its tectonic evolution has always been nature of this rift event, in contrast to the short-lived and that of an active margin, affected first by multi-episodic efficient opening of the Atlantic Ocean, continues to rifting, and then by plate-margin subduction and puzzle.
    [Show full text]
  • Tectonic Motions of the Western United States
    Explore Tectonic Motions of the Western United States Student worksheet Are the tectonic plates still moving? How do know? Let’s explore evidence of the plates moving using current GPS data to see how the land beneath your feet is moving, crumpling, sliding, and stretching. In this activity, you will study the map on the Tectonics Motions of the Western United States poster to look for evidence of different types of crustal motion in the Pacific Northwest, Basin and Range, and California, then consider the hazards and societal impact that might result due to these motions. Explore the poster: Tectonic Motions of the Western United States. 1. What do the red vectors on the map represent? 2. What is the scale for the vectors? [Look at the bottom of the map] Using a ruler, measure the vector scale on the map: • 10 mm/yr = _______ mm • Draw the vector scale bar, representing 10 mm/yr here: 3. What are the yellow lines on the map? 4. Choose 2 vectors from the map, measure the length of each. This is the ground’s velocity at that GPS station. • Using the vector scale bar, determine their velocities, and label their velocities & directions of motion on the map below. 5. Label the map with the state names: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming 6. Outline each region on your map: • Pacific Northwest: Washington / Oregon / Northern California • Basin & Range: Nevada / Utah region • California Questions or comments please contact education @ unavco.org. Page 1 Version: April 9, 2019,
    [Show full text]
  • Floristic Analysis of the Southwestern United States
    Great Basin Naturalist Volume 46 Number 1 Article 5 1-31-1986 Floristic analysis of the southwestern United States Steven P. McLaughlin University of Arizona, Tucson Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation McLaughlin, Steven P. (1986) "Floristic analysis of the southwestern United States," Great Basin Naturalist: Vol. 46 : No. 1 , Article 5. Available at: https://scholarsarchive.byu.edu/gbn/vol46/iss1/5 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. FLORISTIC ANALYSIS OF THE SOUTHWESTERN UNITED STATES Steven P. McLaughlin' Abstract. —A study was made of the distributions of native, terrestrial, \aseular plants occurring in 50 local floras from throughout the Basin and Range and Colorado Plateau physiographic provinces of the southwestern United States. The objectives of the study were to objectively define and describe the floristic elements —assemblages of species with roughly coincident geographic distribution —occurring in the southwestern United States and to deter- mine what such assemblages reveal about the floristic history of the region. The total flora (native, terrestrial species only) of the Southwest is estimated at 5,458 species, 77% of which were recorded in 1 or more of the local floras. Nearly 22% of these species are endemic to the study region. A majority of the species were found to be relatively rare. The average range of a species included only 4 floras, and 90% of the species were recorded from 11 or fewer floras; only 81 species (1.5%) were recorded from 50% or more of the floras.
    [Show full text]
  • National Drought Summary for July 20, 2021
    National Drought Summary for July 20, 2021 Summary Active weather prevailed across much of the South, East, and Midwest, as well as parts of the Plains, into the middle of July, followed by a southward shift in widespread shower activity. Meanwhile, a robust monsoon circulation provided limited Southwestern drought relief, particularly in parts of Arizona, New Mexico, and southwestern Colorado. Farther north and west, however, little or no rain fell in California, the Great Basin, and the Northwest, where dozens of wildfires were in various stages of containment. Smoke and other particulate matter from those fires carried downwind at various atmospheric levels, producing hazy skies and reducing air quality—in some cases thousands of miles from the points of origin. Dry weather extended eastward across the nation’s northern tier as far east as Lake Superior, while heavy rain eased or eradicated drought in the remainder of the Great Lakes region, along with the Northeast. In the driest areas of the northern and western United States, drought’s impact on water supplies, as well as rangeland, pastures, and a variety of crops, was further amplified by ongoing heat. Weekly temperatures averaged as much as 10°F above normal from the interior Northwest to the northern High Plains. On July 19, temperatures as high as 110°F were reported in eastern Montana. Another pocket of hot weather was centered over the middle Atlantic States. In contrast, near- or slightly below-normal temperatures dominated the Plains, Midwest, and South. Northeast Heavy rain extending from New York and northern Pennsylvania into parts of New England resulted in further reductions in the coverage of abnormal dryness (D0) and moderate to severe drought (D1 to D2).
    [Show full text]